IL95508A - Pharmaceutical compositions for transdermal administration - Google Patents

Description

nyn in inn"; 0"Ji9nn D»'TBOII PHARMACEUTICAL COMPOSITIONS FOR TRANSDERMAL ADMINISTRATION 7nm7 DERMAMED C: 11061 Inventors: Avi Gertner Yosef Rubinstein llG6lder.med 1-1124 August 27 , 1990.

Transdermal Administration of Medicaments fiyn -ρ*τ mo inn ino FIELD OF THE INVENTION The present invention relates to pharmaceutical compositions for use in transdermal administration to humans, and to a device and a method for administering medicaments to humans transdermally.

BACKGROUND OF THE INVENTION Various methods and devices are known for administering medicaments through the skin.

In U.S. Patent No. 4 , 638 ,043 (Szycher et al) , there is disclosed a polyurethane matrix for dispensing drugs dispersed therein, primarily for incorporation in a medical patch comprised of successive layers of a substrate, a pressure sensitive adhesive, the drug dispensing matrix and optionally a second layer of adhesive. The matrix may also include (e.g.) polypropylene glycol, polyethylene glycol or glycerine, to soften layer softer and to aid the transport of the drug out of the matrix and into the skin.

As acknowledged in U.S. Patent No. 4 , 767,402 (Kost et al), which discloses the use of ultrasound for enhancing transdermal drug delivery, relatively few drugs are known to be deliverable transdermally, insofar as the majority of drugs will not penetrate the skin at rates sufficiently high for therapeutic efficacy. transdermal drug delivery device which comprises a vinyl gel layer comprising PVC and a drug uniformly dispersed therein, the vinyl gel layer comprising a primary plasticizer for the PVC and an organic nonvolatile gel forming additive in an amount sufficient to form a gel. Examples of such additives are isopropyl palmitate, isopropyl myristate, soybean oil, castor oil, linseed oil, olive oil, mineral oil, petrolatum, caprylic/capric triglyceride and non-ionic surfactants.

In U.S. Patent No. 4,8l8,540 (Chien et al) , there is disclosed essentially a transdermal fertility-controlling polymer matrix dosage unit comprising an impervious backing layer, a polymer matrix disc layer adhered thereto containing microdispersed fertility-controlling estrogen and progestin hormones, and an adhesive layer for securing the dosage unit to the subject. The device may contain, preferably in the adhesive layer, but alternatively or additionally in the matrix layer, a skin permeation enhancing agent, in particular a fatty acid CH (CH ) C00H, where n is 2-16, isopropyl myristate or decyl 3 2 n methyl sulfoxide.

U.S. Patent No. 4,820,525 (Leonard et al) discloses the use of a foamed polyethylene having specified properties, as a drug reservoir in a transdermal/transmucosal pharmaceutical delivery system. Thus, fertility hormones and albuterol were applied transdermally from such reservoirs attached to adhesive tape across nude mouse skin or cadaver skin, using menthol as penetration enhancer.

In U.S. Patent No. 4,822,617 (Panoz) , there is disclosed a device for the transdermal administration of skin-permable drugs (e. g. nitroglycerin, clonidin, methadone and scopolamine) in an ointment, cream or jelly-like carrier, comprising a laminar applicator adapted to receive a predetermined quantity of the drug on a skin-contacting surface thereof, the latter being overlaid by a drug-impervious layer to ensure a unidirectional transfer of the drug to the skin surface. In an exemplified embodiment, the applicator is loaded with a predetermined amount of ointment containing 2% nitroglycerin and lactose in an absorptive lanolin and white petrolatum base formulated to provide controlled release of the active ingredient .

The entire contents of all of the foregoing U.S. Patents are incorporated by reference herein.

It will be appreciated that adhesive patches, by means of which drugs are conventionally administered transdermally to humans, can result in skin irritation and sensitization with prolonged use. Shaving the hair from a suitable area may also be necessary. The present compositions can however conveniently be used (if desired) for transdermal administration to humans by means of apparatus which may be applied non-adhesively, e.g. by securing to the arm or leg by a bandage which is impervious to the drug/carrier combination. 95508/3 It may further be noted that the sense of most of the prior art in relation to transdermal administration to humans is that only a restricted number of drugs are inherently suitable for this form of administration. By contrast with the known art, it is believed that the present invention offers a means of transdermal delivery of a wider spectrum of drugs to humans, than has heretofore been made generally available.

SUMMARY OF THE INVENTION The present invention seeks to provide compositions incorporating medicaments for transdermal administration, as well as a method and device therefor. The present invention accordingly provides in one aspect, a pharmaceutical composition for use in the transdermal administration of a medicament, which comprises an effective amount of a medicament adapted for transdermal administration, in combination with a transdermally transporting effective amount of an essentially non-aqueous carrier for the medicament, which carrier is selected from semisolids and liquids at ambient temperatures, the carrier being further characterized in that it comprises at least one compound selected from esters, excepting monoesters, of CQ_2_| fatty acids, pharmaceutically acceptable aliphatic polyhydroxy compounds and non-volatile paraffins. The invention also provides in another aspect, a device for use in the transdermal administration of a medicament to humans, which comprises a porous, absorbent, perforate and flexible laminar solid support, having absorbed thereon the composition of the invention. The medicament, which may be transdermally administered in the form of 95508/2 the pharmaceutical compositions of the invention, may be an individual medicament or may include two or more individual medicaments, and for the purposes of definition, the term "medicament" in the present specification and claims is to be understood accordingly. In the description which follows, it is of course to be understood that the experiments on animals are carried out for the purpose of in vivo testing of the pharmaceutical compositions of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS Figs. 1A and IB are pictorial illustrations of different embodiments of the device of the present invention; Figs. 2A and 2B are pictorial illustrations of the front and back respectively of apparatus for applying a medicament transdermally to an animal ear; Fig. 2C is a pictorial illustration of the apparatus of Figs. 2A and 2B partially mounted onto the ear of an animal; Fig. 2D is a pictorial illustration of the apparatus of Figs. 2A and 2B fully mounted onto the ear of an animal; Figs. 3A and 3B are pictorial illustrations of the front and back respectively of experimental apparatus for applying a medicament transdermally to an animal ear employed in the Examples set forth hereinbelow; Figs. A, 4B, 4C, *JD and 4E are illustrations taken along lines A-A, B-B, C-C, D-D and in the direction E in Fig. 2A; Figs. 5. 6 and 7 depict respectively the variation of serum levels of 1, 2 or 3 medicaments over a time period, following their transdermal administration* to animals. 95508/1 Figs. 8 and 9 depict the variation of medroxyprogesterone acetate serum levels with time, following transdermal administration* of this medicament to animals.

Fig. 1G depicts the variation of levamisole serum levels with time, following transdermal administration* of this medicament to animals.

Fig. 11 is similar to Fig. 10, but compares transdermal administration* with prior art techniques.

Figs. 12 and 13 show side views of different embodiments of devices according to the invention. *of compositions in accordance with the invention 5a DETAILED DESCRIPTION OF THE INVENTION It may be noted that the perforations in the flexible laminar support (described alternatively herein as a "matrix") enable the user to impart a predetermined desired degree of "breathability" thereto, since even a porous but imperforate matrix may not be adequately breathable so long as the matrix pores at the skin surface are filled with a medicament/carrier combination. In general, the compositions, apparatus and technique of the present invention possess the advantages of enabling either one medicament, or multiple medicaments simultaneously, to be administered transdermally, for a sustained period of time, with positive penetration of the skin and without any shaving or other pretreatment being necessary. Unlike much of the prior art, it appears from the inventors' present experience that the present invention is operable without the additional use of skin penetration enhancers. The combination of medicament and carrier will preferably be in the liquid state at ambient temperatures, although the invention also extends to such combinations which are semi-solid or semi-liquid. Persons skilled in the art will be aware that combinations of medicament and carrier in the liquid state, for transdermal administration, are relatively rare in practical terms.

The medicaments utilized herein may be any medicament adapted for transdermal administration and may include, for example, at least one member selected from reproduction modulating agents, anthelmintics, antibiotics, antiparasitics, antiinflammatory agents, bronchodilating agents, cardiovascular agents and antiallergic agents. 6 95508/2 More particularly, the medicament may comprise, by way of example, at least one member selected from the following subgroups, namely: (i) reproduction modulating agents such as estradiol, progesterone, medroxyprogesterone, medroxyprogesterone acetate, megestrol acetate and testosterone; (ii) anthelmintics such as levamisole, ivermectin, mebendazole and pyrantel ; (iii) antibiotics such as semisynthetic penicillins (e.g. ampicillin, amoxycillin), tetracyclines (e.g. oxytetracycline) and cephalosporins (e.g. cephalexin) ; (iv) antiparasitics such as metronidazole; (v) antiinflammatory agents such as diclofenac sodium, ibuprofen and indomethacin; (vi) bronchodilating agents such as aminophylline, theophylline, terbutaline and salbutamol; (vii) cardiovascular agents such as propanolol, metoprolol and clonidine; (viii) antiallergic agents such as chlorpheniramine and mebhydroline.

It is to be emphasized that the present invention is not to be construed as being restricted, as regards transdermal administration, to the medicaments which fall into one or other of the sub-groups (i) to (viii) recited above, nor is it to be construed as limited to the specified medicaments within each sub-group, these specified medicaments being merely exemplary. 7 95508/2 As has been indicated above, experiments on animals are carried out in the present context for the purpose of in vivo testing of the pharmaceutical compositions of the invention. More particularly, by using in such experiments sheep (40-70 kg.) or young calves (50-80 kg.), which approximate the weight of adult humans, it is believed that the results should be especially indicative of the utility of the present invention. Apparatus for carrying out such experiments is described in the passages which follow.

Thus, such test apparatus for transdermal administration by application of medicaments non-adhesively to the skin of animals may comprise a removable enclosure arranged to be non-invasively mounted onto an animal ear, and incorporating a matrix including the absorbed carrier/matrix combination. Such enclosure may be e.g. a glove-like enclosure arranged to fit over the ear and having a selectable closure associated therewith. The selectable closure may comprise, for example, a zip fastener, or an arrangement of clips or other fasteners which engage each other peripherally of the ear. Alternatively, the removable enclosure may comprise a pair of planar members which are urged together in engagement by a resilient device.

The above-mentioned removable enclosure may be arranged to apply medicaments to two opposite surfaces of the ear. Alternatively, a medicament may be applied on only one of the opposite surfaces. As further alternatives, more than one medicament may be applied on a given surface or two or more 8 95508/2 different medicaments may be applied on different surfaces of the enclosure. As yet a further alternative, different medicaments may be applied to different ears of the animal.

It may be noted that no aseptic or other preparation of the test animal is required prior to application of the medicament, inasmuch as the enclosure may be mounted on an unprepared and untreated ear. Also, the removable enclosure may be arranged so that in normal application and use, the medicament does not come into physical contact with a person applying or removing the enclosure. In accordance with an embodiment of the invention, the matrix (whether for test purposes or for application to humans) may be configured to provide a desired controlled or sustained release pattern for the medicament (s ) .

In accordance with another embodiment, the device of the invention includes a flexible breathable backing layer adhered to one side of a multilayer system providing a desired controlled or sustained release pattern for the medicament( s) , the multilayer system including the laminar solid support (i.e. the matrix) and at least one other layer such that at least two individual layers in the system possess different absorbabilities for the pharmaceutical composition, and the backing layer has less absorbability for the pharmaceutical composition than any of the individual layers in the multilayer system.

As mentioned above, a carrier for the medicament to be administered transdermally comprises at least one compound selected from esters of Cg_2lj fatty acids, pharmaceutically acceptable aliphatic polyhydroxy compounds and non-volatile 9 95508/2 paraffins. The alcohol component of the ester may be derived, e.g. , from an aliphatic hydroxy compound containing 1-12 carbon atoms, preferably 1-6 carbon atoms, and 1-3 hydroxy groups. Thus, e.g., the esters may be methyl, ethyl, propyl, isopropyl, butyl, hexyl, octyl, decyl or dodecyl esters, or esters with polyhydric alcohols such as ethylene glycol, polypropyleneglycol , glycerol or pentaerythritol.

Non-limiting examples of the acid component of the ester are caprylic, capric, lauric, palmitic, stearic, arachidic, behenic, lignoceric, oleic, elaidic, petroselinic, linoleic, (alpha- )linolenic (9il2,15~octadecatrienoic acid), gamma-linolenic, linolelaidic, arachidic, 11-eicosenoic, 11,14-eicosadienoic, ll.l^.iy-eicosatrienoic, 8,11,14-eicosatrienoic, arachidonic, 5.8,ll,l4,17-eicosapentaenoic, erucic and nervonic acids. According to a particular embodiment of the present invention, the carrier for the medicament comprises monoglycerides , diglycerides , triglycerides, and mixtures thereof, of at least one Cg_2_j fatty acid.

Without detracting from the generality of the carrier component of the matrix of the invention, it will be convenient to use the commercially available natural fats and oils, whether of animal or vegetable origin, which contain mixtures of triglycerides of CQ_2_J fatty acids.

While the carrier components of the matrices of the invention are selected for their ability to transport medicaments transdermally, some of them may possess undesirable side effects, particularly an irritant effect on the skin which may cause 1G 95508/2 swelling and discomfort. In such cases, as well as in cases in which an irritant effect on the skin is caused by the medicament(s) , skilled persons will be aware of the possibility of mitigating such side-effects by the addition of e.g. antiinflammatory agents or antihistamines.

Soybean oil has been found by the inventors to be particularly useful as a medicament carrier in the present context, and their experience has been that this oil is compatible with the skin and does not e.g. cause inflammation or swelling. Accordingly, having regard to the constitution of soybean oil, in accordance with a particular embodiment of the invention, there may be utilized as carrier a natural oil in which a major proportion of the fatty acid content consists of ^18-24 polyunsaturated fatty acids, i.e. such acids having two or more ethylenic bonds in the molecule. More preferably, a major proportion of said fatty acid content is selected from linoleic and linolenic acids. In accordance with a different embodiment, the carrier in the inventive compositions is characterized in that it comprises at least 40 (preferably at least 15%. more preferably at least 90%) by weight of at least one ester of at least one C2g_2_j fatty acid.

Reference is now made to Fig. 1A, wherein there is shown, in accordance an embodiment of the device of the invention, a porous, absorbent, perforate and flexible laminar solid support (i.e. matrix) 10, of "Spontex" (trade mark) sponge, in which the pharmaceutical composition of the invention is 11 95508/1 absorbed, and In which circular perforations 12 of diameter Ί mm. had previously been made, the centers of which were approximately 8 mm. apart.

It will be appreciated that the particular support material used, as well as the nature and size of the perforations therein are merely illustrative and not limitative. Thus, where in the present specification and claims, reference is made to "perforate" material, this term is intended to be widely construed. It includes perforations made in the course of manufacture as well as perforations made after manufacture. Moreover, this term includes microperforations which may be clearly seen only with the aid of a microscope, as well as larger perforations which may be seen with the naked eye. The size of suitable perforations will be decided on the basis of factors such as the nature and concentration of the various components of the inventive pharmaceutical composition, and will be determinable by a person of average skill in the art, having in mind that the size of the perforations should be such that they do not become easily clogged up in the course of use. The matrices thus produced were utilized in the field trials described below.

Fig. IB shows another embodiment of the device of the invention, in which a flexible breathable backing layer 14 is adhered to one side of the laminar solid support 10, the backing 11a layer having less absorbability for the pharmaceutical composition, than laminar solid support 10. Thus, for example, layer 14 can be a denser sponge than support 10, with the result that when surface 16 of the laminated composite is applied to the skin, the pharmaceutical composition will be exuded from surface 16 rather than from backing layer 14.

It will be appreciated that the device of the invention such as illustrated in Figs. 1A and IB may be applied to a desired site , e.g. on the upper arm, forearm, leg or thigh, and held in position, i.e., maintained in contact with the skin, by known means. Non-limiting examples of such known means are breathable bandages such as of cotton, stockinette or elastic mesh, including tubular bandages such as "Colufix" (trade mark) tubular net bandage; "sweat bands" used by athletes and applied to the wrist or forehead; and "Micropore" (trade mark) type tape.

Reference is now made to Figs. 2A - 2D and 4A -4E, which illustrate the structure and mounting of a removable medicament-bearing enclosure (for the animal experiments), indicated generally by reference numeral 60, which comprises an inner ear portion 62 typically formed of a perforate web material of plastic, metal or any other suitable material.

The inner ear portion 62, serves to support the ear against deformation and includes a medicament-impregnated support holding curved portion 64, which lies against the inner surface of the animal ear and a bridge member 66 which supports the desired curvature of portion 64 and maintains spacing of the 12 enclosure as desired. Associated with inner ear portion 62 and preferably integrally formed therewith is an outer ear wrap portion 68 and a collar portion 70· Preferably the inner ear portion 62 is formed of material which is somewhat more rigid than the material used for the outer ear wrap portion 68 and the collar portion 70.

The outer ear portion 68 is typically formed of a perforate web material of plastic, metal or any other suitable material which is somewhat stretchable. The collar portion 70 may be formed of identical material but should have limited stretchability . As noted above in earlier described embodiments, the medicament is provided on a perforate solid support (e.g. in the form of a device such as that illustrated in Fig. 1A) " 2 mounted on surface 64 of the inner ear engaging portion 62 and on surface 7 of outer ear wrap.

Fig. 2C illustrates initial insertion of the inner ear engaging portion 62 into the ear of an animal and Fig. 2D illustrates complete fastening of the enclosure 60 onto the animal ear. It is noted that the collar portion is adjustably fastened about the narrow part of the ear closest to the head of the animal, in order to retain the enclosure on the ear. When it is desired to remove the enclosure, it is usually sufficient to unfasten the collar portion and to slide the enclosure off the ear.

In the illustrated embodiment, bayonet type fasteners 76 are employed, it being understood that any suitable type of 13 95508/2 fasteners may be employed. It is appreciated that in the illustrations the enclosure for a right ear is shown. The enclosure for the left ear is configured correspondingly.

It is noted that the fastening arrangement on the outer ear wrap portion is such that various differently sized ears may be readily accommodated by a universal enclosure. Different sized enclosures may however be required for full grown cows and calves, for example.

In the illustration, the outer ear wrap portion includes a slit 80 between adjacent strap portions 82 and 84 , in order to accommodate the curvature of the ear. Depending on the construction of the enclosure, this slit may be eliminated.

A device for transdermal administration in accordance with the invention may comprise a matrix, and a flexible breathable backing layer which may be adhered to one side of said laminar solid support, said backing layer having less absorbability for the pharmaceutical composition, than said flexible laminar solid support; and wherein said laminar solid support is preferably configured to provide a desired controlled or sustained release pattern for said medicament. Such a device preferably includes a flexible breathable backing layer adhered to one side of a multilayer system providing a desired controlled or sustained release pattern for said medicament, wherein said multilayer system comprises a plurality of porous, absorbent, perforate and flexible layers and includes said laminar solid 14 95508/2 support and at least one other layer, and said backing layer has less absorbability for said pharmaceutical composition than any of the individual layers in said multilayer system; preferably at least two individual layers in said system possess different absorbabilities for said pharmaceutical composition. In one embodiment, the pharmaceutical composition is absorbed on at least one layer and possibly even all of the layers of the multilayer system, in addition to that absorbed on said laminar solid support.

Moreover, the device according to the invention may include a multilayer system providing a desired controlled or sustained release pattern for the medicament, and comprising a plurality of porous, absorbent, perforate and flexible layers; it includes the laminar solid support and at least one other layer, as well as a flexible, breathable backing layer which may be adhered to one side of the multilayer system and has less absorbability for the pharmaceutical composition than any of the individual layers in said multilayer system; preferably at least two individual layers in said system possess different absorbabilities for said pharmaceutical composition. In this embodiment, the medicament is impregnated in at least the layer of the multilayer system remote from the backing layer, and at least the laminar solid support has absorbed thereon a substance selected from a transdermally transporting effective carrier for the medicament as defined herein and an admixture of said carrier with medicament, whereby when the device is applied to the skin, the pharmaceutical composition of the invention is formed on at 15 95508/1 least the layer of the multilayer system remote from the backing layer and is thus available for transdermally transporting the medicament. Impregnation of medicament in at least the layer of the multilayer system remote from the backing layer is achieved by any method known to persons skilled in the art, as e.g. by absorption of a solution containing the medicament by the appropriate layer material (s), followed by evaporation of the solvent, for example by lyophilization.

Fig. 12 shows a side view of a particular embodiment of a device according to the present invention, comprising a matrix 12G, e.g. one such as that depicted in Fig. 1A, having a flexible breathable backing layer 122 adhered thereto. Fig 13 shows a side view of another embodiment of the device of the invention, comprising a matrix 130, e.g. one such as that depicted in Fig. 1A, having a flexible breathable backing layer 132 adhered thereto, which is included in a multilayer system shown generally by the reference numeral 134 , which multilayer system consists of at least two layers, i.e. layer 130 and at least one other layer l40. The multilayer system can of course otherwise consist of three or more layers including e.g. layers 142 and 144. Fig. 13 is purely illustrative and does not limit the number of layers in the system or their order. The different layers in the system may have the same, similar or different absorbabilities for the pharmaceutical composition, and will be designed to dispense such composition at the layer nearest the skin so as to transdermally administer the medicament(s) therethrough, e.g. in one of the alternative modes which have been described hereinbefore. 15a 95508/1 In the Examples, below, there are prepared and transdermally administered to animals, as models for human therapy, certain compositions including one or two medicaments selected from progesterone, estradiol and testosterone, or all three together, as well as other compositions including medroxyprogesterone (as acetate) , levamisole or ivermectin. It will of course be appreciated that these medicaments represent exemplary non-limiting embodiments of the invention, which is also applicable to the transdermal administration of other medicaments. These experiments show on the one hand that one or a number of medicaments (simultaneously) may be administered transdermally according to the invention. The possibility of simultaneous administration of a plurality of medicaments is of importance because it is convenient and also ensures patient compliance, since it is known that patients tend to miss doses with the increase in the number of separate medicaments to be administered. On the other hand it will be appreciated that the progesterone, estradiol and testosterone tested may be regarded as representing the classes of progestins, estrogens and androgens. Estrogen replacement is known to alleviate undesired symptoms in menopausal and post-menopausal women; it has also been reported that supplementation of estrogen by progestin may also be beneficial. Also, the estrogen + progestin combination is used for contraception. Androgen therapy is known for a number of applications, as is estrogen and/or progestin therapy. 15b 95508/1 As regards medroxyprogesterone (as acetate), particular applications are for the treatment of secondary amenorrhea or of abnormal uterine bleeding due to hormonal imbalance (in the absence of organic pathology such as fibroids or uterine cancer), the usual dosage being 5~10 mS- tablets daily for 5~10 days; and for adjunctive therapy and palliative treatment of inoperable, recurrent and metastatic endometrial carcinoma or renal carcinoma, in which cases, initially 400-1000 mg. per week is administered intramuscularly in the form of a sterile aqueous solution, the dosage rate being reduced to 400 mg. per month if improvement is noted within a few weeks or months .

Levamisole is widely used as an anthelmintic, and possesses a broad spectrum of activity against gastrointestinal and systemic nematodes; in particular, it is used for the treatment of ascariasis (roundworm), when the usual dosage form is 5O-I O mg. as tablets, and of ancylostomiasis (hookworm). It also reputedly possesses immunomodulatory action. It is normally administered orally as the hydrochloride. Ivermectin has recently shown promise in the treatment of onchocerciasis in man, when a single oral dose of 12 mg. (or about 200 yg./kg. body weight) is usual.

The invention will now be illustrated by the following non-limiting Examples. 15c 95508/1 EXAMPLE I: Preparation of Medicament-Soybean Oil Mixture and Matrix containing it.

Soybean oil containing 400 mg./l. butylated hydroxytoluene (antioxidant) was heated at 38°C and progesterone was added (to obtain ( 18.7 g- Α · soybean oil), the mixture being thoroughly stirred for 1 minutes; the product was labelled "A".

To product "A", there was added 17P~estradiol (a concentration of 10.7 g«/l« soybean oil was obtained), the mixture again being thoroughly stirred for 15 minutes at 38°C; the product was labelled "B".

To product "B", there was added testosterone (a concentration of 23.6 g./l. soybean oil was obtained), the mixture again being thoroughly stirred for 15 minutes at 38°C; the product was labelled "C" .

Products "A" , "B" and "C" were used to impregnate pieces of "Spontex" (trade name) absorbent sponge illustrated in Fig. 1A, which has been described above. The matrices thus produced were utilized in the field trials described below. 15d EXAMPLE II: Transdermal Administration of Progesterone to Ewes. Method. The study was performed in May 1990 on five sexually mature ewes of mixed breeding (Table 1) of proven fertility, cycling normally during anoestrus and on an adequate nutritional diet. The ewes were part of a 200-sheep flock housed in a sheep shed in the central plain region of Israel.

Table 1 ; characteristics of the study animals Ewe No. Age* (years) Weight* (kg. ) Breed 1 3 40 Merino/Finnish Landrace 2 1.5 50 Awasi/Finnish Landrace 3 1.5 60 Merino/Finnish Landrace 4 3 70 Merino/Awasi/Finnish Landrace 5 2 50 Merino/Finnish Landrace *approximate Enclosures 100 substantially as illustrated in Figs. 3A and 3B» were employed. The elements of enclosure 100 are similar to those described in connection with Figs. 2A - 2D and 4A - 4E. Each ear device contained two similar drug matrices 102 with respect to the amount of progesterone. Each of the two matrices, of a type similar to that illustrated in Fig. 1A, above, had a surface area approximately 60 cm.2 and contained approximately 15 ml. of product "A" (as prepared in Example I) and thus about 276 mg. progesterone. The matrices were maintained in contact with the skin surface on each side of one only of the animal' s ears . The skin surfaces had not been shaved or otherwise prepared in any manner prior to attachment of the device containing the two drug matrices. The matrices were maintained on ewes nos. 1 and 3 for 16 10 consecutive days and on ewes nos. 2, 4 and 5 for 13 consecutive days.

Prior to attaching the progesterone-containing devices, morning venous blood samples were taken from the jugular veins of each ewe on two consecutive days. Twelve hours after the second blood sample was taken the devices were attached. Twelve hours thereafter a morning blood sample was taken and then every morning except Saturdays until each device was removed. Twelve hours after each device was removed from ewes nos. 1 and 3. a morning blood sample was taken and then on the following two mornings; the devices were removed from the other ewes after 13 days. All five ewes were then injected with 600 i.u. PMSG (as a standard practice at the end of synchronization treatment) . Forty-eight hours after PMSG administration, blood samples were taken from all five ewes and 24 hours later the last blood sample was taken. Serum levels of progesterone were assayed in duplicates by solid-phase radioimmunoassay using D.P.C. Coat-A-Count methods. After the last blood sample was taken, circular biopsies (5 mm. diameter) were taken from each animal, three from the treated ear and three from the untreated ear (control) . One biopsy was taken from the center of the ear and the other two from the periphery of the distal part of the ear.

The ear samples were preserved in k% buffered formaldehyde saline. Transversal sections of the ear samples were prepared after hydration and embedding in paraffin wax. The sections were stained with hematoxylin and eosin, and were subsequently examined microscopically by a certified toxicological pathologist. 17 Results . Pretreatment progesterone serum levels averaged approximately 0.3 ng./ml. Progesterone serum levels from morning blood samples, taken 12 hours after the device was attached, were higher in all ewes than pretreatment values and ranged from 0.5 to 1.7 ng./ml., an average increase of 1 ng./ml. During the treatment period, progesterone serum levels ranged from OA to 9 A ng./ml. In all five ewes sustained release profiles were observed. Progesterone serum levels from morning samples taken 2k hours after the device was removed (10 days) from ewes 1 and 3 (first post-treatment blood sample) were not different from pretreatment values and remained so for the next 7 days. Forty-eight hours after the device was removed from the other three ewes and the PMSG injected, the first blood sample was taken. Serum progesterone level from these samples as well as those taken 24 hours later averaged 0.3 ng./ml., i.e the same as the pretreatment levels. Mean progesterone serum levels during the study for the 3 ewes which were treated for 13 days are shown in Fig. 5.

The ears to which the devices had been attached showed slight hair loss, slight scaling in three cases and slight diffuse acanthosis. Otherwise, there was evidence that observed light wounds were due to structural imperfections in the laboratory-made prototype device, which should be avoidable in a standard manufactured model. 18 EXAMPLE III: Transdermal Administration of Several Medicaments to Cattle from a Single Matrix.

Method. This study was performed in May 1 90 on six healthy Holstein calves kept in individual cages and fed normally; the location was a dairy farm in the central plain of Israel.

Table 2: characteristics of the study animals Calf No. Sex Age (months) Weight* (kg. ) 1 M 2 60 2 M 3 70 3 M 3 80 4 M 1.5 50 5 M l 55 6 F 2 60 *approximate Enclosures 100 substantially as illustrated in Figs. 3A and 3B, were employed. The elements of enclosure 100 are similar to those described in connection with Figs. 2A - 2D and 4A - 4E. Each ear device contained two similar drug matrices (of a type illustrated in Fig. 1A, above) with respect to the amount of active agents and surface area (each approximately 60 cm.2 ) ; the matrices were thus maintained in contact with the skin surface on each side of one only of the animal's ears. Each matrix contained approximately 10 ml. of product "B" or "C" (see Example I, above) . The skin surfaces had not been shaved or otherwise prepared in any manner prior to attachment of the device containing the two drug matrices. The matrices applied to the five male calves contained in each matrix approximately 97 mS- 19 17f¾-estradiol and approximately I87 mg. progesterone. The matrices applied to the female calf contained in addition to estradiol and progesterone, approximately 230 mg. testosterone in each matrix. The drug matrices were maintained on the female calf (no. 6) for 6 consecutive days. On the male calves, the matrices were maintained on nos . 1 and 5 for 8 consecutive days , on nos. 2 and 3 for 3 consecutive days and on no. for 16 consecutive days.

For 3 consecutive days prior to attaching the devices, morning venous blood samples were taken from the jugular veins of each calf. Twelve hours after the third blood sample was taken the devices were attached. Morning blood samples were then taken every morning except Saturdays; 12 hours after the last blood sample was taken, each device was removed. Twelve hours after each device was removed, a morning blood sample was taken and then again on each of the following three days.

Serum levels of progesterone, 17(J-estradiol and testosterone (only assayed on the female calf) were determined in duplicates by solid-phase radioimmunoassay using D.P.C. Coat-A-Count methods. After the last blood sample was taken, six circular biopsies (5 mm. diameter) were taken from each animal; three from the treated ear and three from the untreated ear (control) . One biopsy was taken from the center of the ear, one from the ear fold and one from the periphery of the distal part of the ear (opposite the ear fold) .

The ear samples were preserved in % buffered formaldehyde saline. Transversal sections of the ear samples 20 were prepared after hydration and embedding in paraffin wax. The sections were stained with hematoxylin and eosin, and were subsequently examined microscopically by a certified toxicological pathologist.

Results. Pretreatment estradiol (<10 pg./ml.) and progesterone (<0.1 ng./ml.) serum levels were less than the lower limit of detection in all six calves and the testosterone levels in the female calf at this period were also lower than the limit of detection ( In two out of the six calves, levels of these medicaments following attachment of the device were sporadic, while in the other four, a sustained release profile was observed. Two examples of the sustained release profiles are presented in Figs. 6 and 7· The ears to which the devices had been attached showed moderate diffuse acanthosis in some cases. Otherwise, there was evidence that observed ulceration was due to structural 21 95508/2 Imperfections in the laboratory-made prototype device, which should be avoidable in a standard manufactured model.

Conclusions. The results show that the utilized device enables several drugs to be simultaneously administered transdermally from a single matrix to cattle for an extended period of time under field conditions, while being compatible with the animal's skin. Further, drug blood levels can be rapidly achieved and can quickly return to pretreatment levels after the removal of the device.

EXAMPLE IV: Animal Tests on Various Oils as Carriers for Transdermally Administered Medicaments .

Method The study was conducted on a farm located in the central plain region of Israel during September 1990. Male lambs of mixed breeding (Merino/Romanoff and Merino/Finnish Landrace) aged 4- months and weighing 45~55 kg. were fed hay and commercially available concentrated feed pellets once a day and had free access to water. Nine pharmaceutical compositions based on the following non-volatile oils, namely ( 1 ) peanut oil, (2) 0·' 10 almond oil/walnut oil admixture, (3) rapeseed oil, (4) soybean oil, (5) corn oil, (6) liquid coconut oil, (7) glycerol, (8) propylene glycol, and (9) paraffin oil were tested in groups of 3-4 lambs. Each of the nine compositions was prepared by mixing overnight at 38°C, 100 ml. oil with 500 mg. of ^-estradiol as medicament and 40 mg. of butylated hydroxytoluene as antioxidant. The fatty acid content of the vegetable oils (1) to (6) and the estradiol concentration in each of oils ( 1) to (9) , were determined, and are shown in Table 3. below. 22 95508/1 Table 3_ Fatty Acid (%) Estradiol (mg./ml. ) Oil C C C C C C 16:0 16:1 18:0 18:1 18:2 18:3 (1)* 10.57 3.61 42.40 36.92 1.07 4.54 (2) 8.23 2.24 21.01 55.95 12.57 4.94 (3) 5-39 0.21 1.54 58.46 22.83 11.57 5.34 (4) 10.48 3.88 22.04 55.36 8.24 4.76 (5) 10.11 1.85 28.49 58.38 1.17 5.48 (6)* 4.10 (7) 4.91 (8) 5.12 (9) 6.34 contained also 0. 4# C 20:0 ♦contained 54.2% C , 45.1 C , 0.80 C 8:0 10:0 12:0 Experiments were conducted with preliminary prototype ear devices. To each such device, a matrix was attached. The matrix was made up of 4 mm. thick Spontex(R) absorbent sponge in which circular perforations of 4 mm. diameter had been made, the centers of the circles being approximately 8 mm. apart. The surface area of the matrix was 110 cm.2 (55 cm2 surfaces covering the outer and inner surfaces of the ear, respectively) . This matrix was impregnated with 16 ml. of the composition under test, and the system (ear device with impregnated matrix attached) , which weighed approximately 0 &· was mounted on the lamb's ear. 22a 95508/1 The skin surfaces of the ear were not shaved or prepared in any manner prior to mounting of the device. The systems were removed from the lamb's ear after four consecutive days.

Medicament penetration of the skin was assessed by determining 17£-estradiol concentration (by solid phase radioimmunoassay) in the serum at intervals over period of the investigation. In the morning (0700-080G) venous blood samples were taken from the jugular vein on three consecutive days before mounting the device; in all animals except two, it was found that the serum did not contain a measurable quantity of 17 -estradiol (<10 pg./ml.), the exceptions contained 12.3 and 17.1 pg./ml. The device was then mounted and a blood sample was taken after two hours and on consecutive mornings following attachment of the device. After four days of attachment, the device was removed. Morning blood samples were taken on the three consecutive days following removal of the device.

After the device was removed from the lamb's ear, the treatment site and the whole ear were examined. Following physical examination, samples were taken from the ear for biopsy.

Results of these tests are summarized in Table 22b 95508/1 Table Oil no. of Estradiol serum Estradiol serum animals/ concentration concentration result of after post-administration examination 2 hrs 1 day 4 days +1 +2 +3 (days) ( 1 ) 4§ d c+ d 0 G G (2) 3» d c c+ G G G ( 3 ) 4 · c- c G 0- 0- 0- (¾) 3» c- e c- a- 0- Q- ( 5 ) 3§ c- b c- a c- 0 ( 6) 3* g f f- 0 G G- (7 ) 4 · Θ a- 0 a- 0 0- (8) 4* f f- c c- a- G- (9 ) 4* e- a- G 0- G- G- KEY TO TABLE 4 : Estradiol serum concentration G-..no animals had significant amounts > 2G pg./ml.

G...no more than 1/3 animals had significant amounts > 2G pg./ml. a-.. at least 2/4 animals had over 19 - 5 pg./ml. a... all animals had over 19 · 5 Pg./ml. b...all animals had over 28 pg./ml. c-..at least 2/3 animals had at least 30 pg./ml. c...all animals had over 38 pg./ml. c+..all animals had over 42 pg./ml. d...all animals had over 57 pg./ml. e- . .3/4 animals had over 70 pg./ml. e...all animals had over 67 pg./ml. f-..all animals had over 92 pg./ml. f...all animals had over 145 pg./ml. g...all animals had over 300 pg./ml.

Physical observation of ear, post administration §...no abnormality detected in at least 50% of animals ■...no more than slight/moderate swelling in at least 2/3 animals ♦...ulceration, encrustation or moderate/severe swelling in at least 2/3 animals 22c 95508/1 Discussion of Results As already pointed out, the ear devices were prototypes. Therefore, this discussion will be subject to the reservations that they are to be regarded as preliminary results which may point to the need for further investigations, and are intended principally to convey whether the substances tested as carriers are likely to be effective in transporting medicaments through the skin, and to obtain an indication of skin compatibility of these substances. Subject to these reservations, the following trends may be observed with regard to transdermal transport of the estradiol to the serum.

Two hours after administration, the descending order of carrier efficacy was as follows: 6 > 8 > 9 > 1.2 > 3~5 > 7, and in all cases except that of glycerol, there was a significantly increased concentration of estradiol in the serum of the test animal, liquid coconut oil being the most effective carrier, followed by propylene glycol.

At one day after administration, the descending order had become: 6 > 8 > 4 > 1 > 2,3 > 5 > 7,9; at this stage, soybean oil, in third place after liquid coconut oil and propylene glycol, had become more effective than at the two-hour stage, and the initial efficacy of paraffin oil had fallen away.

At four days after administration, the descending order had become: 6 > 1 > 2 > 8 > Ί.5 > 3,7.9; at this stage, rapeseed oil had joined glycerol and paraffin oil as being apparently 22d 95508/1 relatively ineffective, while peanut oil and to a lesser extent the S0:10 almond/walnut oils admixture, had improved their performance as medicament carriers.

As may be seen from Table in most cases the medicament did not persist in the animal's serum, once the device was removed, a result which was not entirely surprising. Exceptionally, however, the medicament carried transdermally by corn oil and by propylene glycol, maintained a significant presence in the serum in the 1-2 day period following removal of the device.

As regards the effect of administration on the test animal's ear, it is believed that the sporadic findings of ulceration in the case of liquid coconut oil and propylene glycol were most probably caused by accidental traumatic injury (i.e. by scratching), and should therefore not adversely effect the utility of these particularly effective medicament carriers. In general terms, it is concluded that vegetable oils and propylene glycol are particularly effective as carriers for medicaments to be administered transdermally, but that glycerol and paraffin oil might nevertheless find some application for this purpose.

Insofar as it is believed that the screening method employed in this Example is an embodiment of a more general method which possesses both novelty and inventivity, there is further provided in accordance with the present invention a method for testing the potential viability for transdermal 22e 95508/1 administration in human applications of a mixture of a preselected medicament with a preselected carrier for the medicament, which method comprises applying non-adhesively to the skin of an animal, for a preselected time period, a matrix which comprises a porous, absorbent perforate solid support, having the mixture absorbed thereon, and assaying the blood levels in the animal of the medicament over the preselected time period.

EXAMPLE V: Relative Medicament Penetration through the Inner and Outer Ear Skin Surfaces of Male Calves In the specific examples herein of transdermal administration of compositions in accordance with the invention, a device (sometimes referred to as AV-DDS) has been used in which the medicament in question was applied to both inner and outer skin surface of either one or both ears of animals. The present study is intended to examine the relative penetration of medicament through these two different skin surfaces.

Method This study was conducted on a dairy farm located in the central plain region of Israel during August, 1990. It was carried out on five healthy male Holstein calves having the following ages and weights: #2^ , 2.5 months, ~60 kg.; #6θ4 , 2.5 months, ~70 kg.; #621 , 2.5 months, ~70 kg.; #298 , 2.5 months, ~75 kg.; and #307. 3 months, ~90 kg. Each calf was kept in an individual cage, but was fed and otherwise treated normally.

Experiments were conducted with laboratory-made ear device prototypes and preliminary laboratory-made dosage forms. To each 22f 95508/1 ear device, there were attached one dosage form to be applied to one surface of the animal's ear, and a different dosage form to be applied simultaneously to the other surface of the same ear. There was no contact between the different dosage forms. The skin surfaces of the ear were not shaved or otherwise prepared in any manner, prior to attachment of the device to the animal's ear.

The matrix for each dosage form was made of a 4 mm. thick Spontex(R) absorbent sponge in which circular perforations of 4 mm. diameter were made, the centers of which were approximately 8 mm. apart. The surface area of each matrix was 60 cm.2, and was applied to one surface of the ear only, as stated. Each matrix was impregnated prior to attachment, with 11 ml. of either a mixture of 25 mg./ml. progesterone (Sigma) in soybean oil so as to contain 275 ng« progesterone, or 15 mg./ml. 17 ~estradiol (Sigma) in soybean oil so as to contain 16 mg. estradiol. The AV-DDS devices in which the impregnated matrices were incorporated were maintained on each animal for 2 consecutive days. Morning (Ο7ΟΟ-Ο8ΟΟ) venous blood samples ( 10 ml.) were taken from the jugular vein of each animal before administration of the medicament on either 1 or 2 (consecutive) days, immediately prior to attachment of the device and then at 1 and 2 days thereafter. Serum concentrations of the medicaments were assayed in duplicates by solid phase radioimmunoassay. 22g 95508/1 Experiment JL The device mounted on calves #24 , #6θ4 and #621 maintained the progesterone dosage form in direct contact with the inner ear surface and the estradiol dosage form in direct contact with the outer surface of the same ear.

The device mounted on calves #298 , and #307 maintained the progesterone dosage form in direct contact with the outer ear surface and the estradiol dosage form in direct contact with the inner surface of the same ear.

Experiment 2 After it had been determined that the animals' serum levels of the medicaments had the same values as before Experiment 1 , the device was mounted on calf #621 and maintained 11 ml. soybean oil (without medicament) in direct contact with the inner ear surface and the estradiol dosage form in direct contact with the outer surface of the same ear, while the device mounted on calf #298 maintained 11 ml. soybean oil (without medicament) in direct contact with the outer ear surface and the progesterone dosage form in direct contact with the inner surface of the same ear.

Two devices were mounted on calf #307 one on each ear. The device mounted on the left ear maintained 11 ml. soybean oil (without medicament) in direct contact with the outer surface of that ear and the estradiol dosage form in direct contact with the inner surface of the same ear, while the device mounted on the right ear maintained 11 ml. soybean oil (without medicament) in 22h 95508/1 direct contact with the inner surface of that ear and the progesterone dosage form in direct contact with the outer surface of the same ear.

Results The results are shown in Table below. It is noted that pretreatment serum levels of progesterone (<0.1 ng./ml.) and estradiol (<1G pg./ml.) were lower than the limit of detection in all the calves, in both experiments.

In Experiment 1, progesterone was detected in all the blood samples taken during the treatment period with the exception of calf #298, in which progesterone was detected on day 2 and not on day 1. Estradiol was detected in all the blood samples taken during the treatment period.

In Experiment 2, progesterone was detected in all the blood samples taken during the treatment period from calves #2 8 and #307· Estradiol was detected in all the blood samples taken from calves #621 and #307 during the treatment period.

Conclusion It may be noted from the results tabulated below, that there was no significant difference between the penetration of either medicament, through either the hairy outer skin surface of the ear, or the waxy inner skin surface of the ear. 22i 95508/1 Table 5_ Medicament Ear Surface Calf # Medicament Serum Concentration* Day No. -2 -1 0 1 2 progesterone inner 245 <0.1 <0.1 <0.1 0.42 Ο.69 (Expt. 1) 604 <0.1 <0.1 <0.1 0.12 0.42 621 <0.1 <0.1 <0.1 Ο.95 0.44 progesterone outer 298 <0.1 <0.1 <0.1 <0.1 0.16 (Expt. 1) 307 <0.1 <0.1 <0.1 Ο.37 0.4i estradiol outer 245 < 10 < 10 < 10 213.6209.8 (Expt. 1) 604 < 10 < 10 < 10 110.3 250.6 621 < 10 < 10 < 10 208.1 I7 .9 estradiol inner 298 < 10 < 10 < 10 214.6 124.4 (Expt. 1) 307 < 10 < 10 < 10 319.6 85.2 progesterone outer(R) 307 - <0.1 <0.1 0.2 0.3 (Expt. 2) inner(R) 298 <0.1 <0.1 0.4 0.2 estradiol outer(R) 621 - < 10 < 10 187.O 44.0 (Expt. 2) inner(L) 307 < 10 < 10 23.Ο I58.6 progesterone, ng./ml., estradiol pg./ml.

EXAMPLE VI: Continuous Transdermal Administration of Medroxyprogesterone Acetate to Sheep Method The study was conducted on a farm located in the central plain region of Israel during October-November, 1990· Six lambs were fed once a day with commercially available concentrated feed pellets; hay and water were available ad 22j 95508/1 libitum. Two experiments were performed. In each experiment a different medroxyprogesterone acetate (MPA) dosage form, in accordance with the invention, was adsorbed in a matrix, which was incorporated into the AV-DDS device as previously described in detail herein.

In the first experiment, performed on two male lambs, 800 mg. MPA was stirred overnight at 37°C with 70 ml. soybean oil, the mixture impregnated into the 110 cm.2 perforated sponge matrix (55 cm.2 applied to the outer and inner ear surfaces), so that each such matrix contained 182.86 mg. MPA. Two such matrices were used per animal, one for each ear simultaneously, and were maintained on the ears for 11 consecutive days; the ear surfaces were not shaved or prepared in any manner prior to applying the devices incorporating the matrices. Venous blood samples ( 10 ml.) were taken from the jugular vein of each lamb before application of the devices, then 1 , 2 and 4 hours thereafter and every morning (0700-0800) for the next 13 days.

In the second experiment, performed on two male and two female lambs, a larger amount of MPA was used, resulting in a concentration of 2 mg. MPA/ml. in soybean oil. Each perforated sponge was in this case impregnated with 8 ml. soybean oil, allowed to stand several minutes, then impregnated with 8 ml. of the MPA-containing composition. Three layers of absorbent paper towels perforated in the same manner as the sponge were attached to each system to cover the sponge, the perforated towels were impregnated with 16 ml. of the MPA-containing composition, whereby each dosage form contained 600 mg. MPA. The system, 22k 95508/1 assembled as before, was mounted on the left ear, and maintained on the animals for 9 and 11 days, respectively, in the case of the two male lambs, and for 1 days in the case of the female lambs. Venous blood samples ( 10 ml.) were taken from the jugular vein of each lamb before application of the devices, then 1 , 2 and 4 hours thereafter and every morning (0700-0800) until the system was removed, and in certain cases after removal of the system. Bioavailability of MPA was determined by assaying the MPA serum concentrations, determined by a gas chromatographic method having a lower limit of detection of 0.25 ng./ml. (PPB) .

Results No MPA could be detected in the serum of any of the lambs, prior to attachment of the system. In the first experiment (see Fig. 8) , MPA was detected in blood samples from one lamb (#99) one hour after the device was applied, and in the other lamb(#96) after 4 hours. MPA was detected in blood from lamb #96 throughout the 11-day treatment period and in blood from lamb #99 during 10 days. 48 hours after the device was removed from lamb #96, MPA could not be detected.

In the second experiment (see Fig. 9) 1 the results were similar to the first experiment, with the following differences. In lamb #770 , MPA was detected in the blood sample one hour after the device was mounted, while in the other 3 lambs MPA was similarly detected two hours after mounting the devices. In the female lambs (#770 and #771) the duration of treatment was 15 days and MPA was detected throughout the period for lamb #770 , 221 95508/1 while for lamb #771 it was detected for lk days. 2 hours after the device was removed, no MPA was detected in blood samples taken from any of the four lambs.

Discussion of results Prior to the treatment with the device containing an MPA dosage form, no MPA could be detected in any of the blood samples taken from the lambs. In most of the blood samples taken 2 hours after treatment commenced, and in all of the blood samples taken k hours after treatment commenced, MPA was detected. MPA serum concentrations ranged from 0.25 ng./ml. (lower limit of detection) to 2.0 ng./ml. in blood samples taken during the treatment period. Both the first and second experiments gave similar results.

The results of this study demonstrate that MPA can be administered transdermally for an extended period of time to sheep. Thus, transdermal administration of MPA to sheep provides a model for the potential use of MPA in transdermal administration to humans.

EXAMPLE VII: Transdermal Administration of Medroxyprogesterone Acetate to Ewes for the Induction of Synchronized Oestrus.

Introduction The present example provides an evaluation of the transdermal technique, when used to artificially induce oestrus to ewes at the end of the normal breeding season under field conditions, as a model for the potential use of MPA in transdermal administration to humans. 22m 95508/1 Method The study was performed over a period of 13 consecutive days in the last week of 1990 and the first week of 1991. on 24 sexually mature Merino/Cambridge ewes of proven fertility, at the end of the normal breeding season. The ewes, which were housed in a sheep shed in the central plain region of Israel, were maintained on an adequate nutritional diet, water being available ad libitum. Of the 24 ewes, 22 were treated with medroxyprogesterone acetate (MPA) according to the known intravaginal method, while the other 2 were treated with MPA according to the present invention. At the end of the 13-day period, each ewe was injected with 600 i.u. of PMSG (Intervet) , oestrus being determined 48 hours later by the standing heat method; ewes exhibiting oestrus were then artificially inseminated.

The MPA dosage form was prepared and used in the following way. A mixture of MPA (Sigma) with soybean oil (23 mg./ml.) was heated to 37°C and stirred overnight. To each of two ear devices, produced in a pilot production facility, a single matrix was attached, each matrix having a surface area of approximately 110 cm.2 (i.e. 55 cm.2 applied to the inner and to the outer ear surface) and consisting of 4 mm. thick Spontex (R) absorbent sponge containing 4 mm. diameter circular perforations, the centers of which were approximately 8 mm. apart. Each matrix was impregnated first with 8 ml. soybean oil and then, after several minutes, with 8 ml. of the MPA/soybean oil admixture. 22n 95508/1 Three layers of absorbent paper towels perforated In the same manner as the sponges were then laid over the latter and Impregnated with 16 ml. of the MPA/soybean oil admixture, thus each dosage form contained 23 x 2Ί = 2 mg. MPA. As indicated, the device containing the MPA/soybean oil admixture was mounted on the animal's ear and kept in place 13 consecutive days; the skin surfaces of the ear had not previously been shaved or otherwise prepared.

Results At the end of the 13_day period, the intravaginal sponges were removed (but had fallen out from 3 of the 22 ewes) and the ear devices were detached. Oestrus was observed in 21 of the total of 2h ewes, i.e. in all except the 3 from which the sponges had fallen out. The present study showed that the transdermal procedure in accordance with the invention was capable of achieving synchronized oestrus in ewes under field conditions.

EXAMPLE VIII: Continuous Transdermal Administration of Levamisole to Sheep .

Introduction Levamisole is widely used as an anthelmintic, and possesses a broad spectrum of activity against gastrointestinal and systemic nematodes, as well as reputedly possessing immunomodulatory action. It is normally administered orally as the hydrochloride. 22o 95508/1 Levamisole Is a stimulant of Nematode ganglia, leading to neuromuscular paralysis of the parasites. Because of its mechanism of action, the peak blood concentration is more relevant to its antiparasitic activity than the duration of concentration.

In cattle, peak blood levels of levamisole occur in < 1 hour after subcutaneous administration. These concentrations then decline rapidly and Q% of the total dosage is excreted in 2k hours, largely in the urine.

Since levamisole acts on the roundworm nervous system, it is not ovicidal. This, coupled with the fact that levamisole is rapidly excreted after administration, can therefore only offer limited protection against reinfestation when administered according to the known art.

It would therefore be advantageous if the anthelmintic action of levamisole could be prolonged after a single administration and thus provide better protection with respect to reinfestation.

The purpose of the present study is to determine whether the incorporation of levamisole in the present transdermal administration system and compositions can achieve levamisole blood levels which are sustained for a longer period than is achieved by the current modes of administration.

Method The study was conducted on a farm located in the central plain region of Israel during October 1990. Male lambs 22p 95508/1 of mixed breeding (Merino/Romanoff and Merino/Finnish Landrace) aged 5~6 months and weighing 45~ 5 kg. were fed hay and commercially available concentrated feed pellets once a day and had free access to water. The lambs were randomly divided into groups I (3 lambs), II (2 lambs) and III (3 lambs), each group being housed in a separate pen.

Venous blood samples ( 10 ml . ) were taken from the jugular vein of each lamb, before treatment, and then 1 , 2 and 4 hours after commencement of treatment. Blood samples were then taken every morning (0700-0800) for the next four days in groups I and III, and for eight days (except day 3) in group II.

Group I was treated with a single 3 ml. intramuscular injection of 225 mg. levamisole in the form of a 7 · 5% solution (Caliermisol) marketed by Laboratories Calier S.A. (Barcelona, Spain) . Groups II and III were treated with the AV-DDS device containing the different levamisole dosage forms. In these experiments, preliminary prototype ear devices produced in a pilot production facility were used. To each such device a matrix was attached. The matrix was made up of 4 mm. thick Spontex(R) absorbent sponge in which circular perforations of mm. diameter had been made, the centers of the circles being approximately 8 mm. apart. The surface area of the matrix was 110 cm.2 (55 cm2 surfaces covering the outer and inner surfaces of the ear, respectively).

A mixture of 20 g. levamisole-HCl , 2 ml. liquid coconut oil and 100 ml. soybean oil was stirred at 37°C overnight. In group II (dosage form "A") each matrix was 22q 95508/1 impregnated with 16 ml. of the levamisole mixture and the system (ear device with impregnated matrix attached) weighed ~50 g. In group III (dosage form "B") each matrix was first impregnated with 8 ml. sunflower seed oil and then with 16 ml. of the levamisole mixture; the system weighed ~57 g- The total amount of levamisole contained in each dosage form in groups II and III was 2 6Ο mg. The skin surfaces of the ear were not shaved or prepared in any manner prior to mounting of the system (AV-DDS) . Levamisole skin penetration was assessed by determining the concentration of levamisole in the serum by a gas chromatographic method; the limit of detection of the assay was O.O5 ug. levamisole/ml .

Results Table 6 shows the amount of levamisole in serum for groups I, II and III, at the indicated time intervals after administration. Prior to administration, no levamisole was detected. These results are depicted graphically in Fig. 10 (group I) and in Fig. 11 (groups II and III) .

Table 6 Group no. of Levamisole serum concentration (pg./ml.) after animals lhr 2hrs hrs 24hrs 4 days 6 days 8 days I* 3 0.8 0.3 O.I7 0 0 II 2 0.05 O.O5 0.05 O.O5 0 III 3 0.2 0.2 0.3 0.2 O.O ** 0 0.^3 0.04 *225 mg. levamisole administered intramuscularly **Ripercol(R) (Janssen) pour-on preparation, the data shown is deduced from the graph in promotional literature 22r 95508/1 Discussion of Results Rapid and sustained levamisole serum concentrations were achieved with both dosage forms "A" and "B" , although the concentration in the case of "A" was low. A more sustained release of levamisole was obtained with dosage form "B" than with the pour-on preparation, though at a somewhat lower concentration than the peak level of the pour-on preparation. As regards rate of penetration of levamisole, transdermal administration according to the present invention resembles an intramuscular injection, but in terms of peak serum concentrations, dosage form "B" resembles the pour-on preparation. However, both transdermally administered dosage forms "A" and "B", are unique in that the period of sustained blood levels is measured in days rather than hours, as compared with both the intramuscular injection and the pour-on preparation, thus providing improved protection against reinfestation. Also, since the present mode of administration is external, treatment can be terminated at any time simply by removal of the system.

EXAMPLE IX: Continuous Transdermal Administration of Ivermectin to Sheep Introduction Ivermectin, a semisynthetic macrocyclic lactone, introduced in 1981, belongs to a group of broad spectrum antiparasitics which have been widely used in the treatment of endo- and ecto-parasites in sheep, horses, swine and cattle; as indicated above, it has recently shown promise for the treatment of oncocerciasis in man. It is a mixture of homologs comprising 22s not less than 80% of 22,23-dihydroavermectin B^a and not more than 20% of 22,23-dihydroavermectin Blb, although there is no difference in the antiparasitic activity of the two.

Ivermectin is absorbed systematically after oral or subcutaneous administration, but is absorbed to a greater degree when given subcutaneously. The route of administration and the nature of the formulation employed affect its disposition profile. Most of the administered dose of Ivermectin is excreted in the feces, the remainder in the urine. Drug residues were reported to be higher in the liver and in fat than in other edible tissues, and the major component of the residues was unaltered Ivermectin.

As with other anthelmintics, efficacy is profoundly affected by both the potency of the drug and its residence time within the treated animal, or its kinetic profile. Several modes of drug administration, unique in terms of applicability only in animal health and restricted mainly to cattle, have been developed to increase the residence time of the active drug in the treated animal. These include unique injectable formulations, pour-on preparations and ruminal boluses.

The AV-DDS system has been developed to achieve, both the features of sustained drug levels and the ability to terminate treatment when desired. This system is an external, non-invasive system which can be readily mounted on the animal's ear, can be as readily removed when desired, and also enables the animals undergoing treatment to be visually identified. The 22t system Includes two components, namely, the device itself (which maintains the medicament dosage in direct contact with the skin for the desired duration of treatment) and the transdermal dosage form attached thereto.

Method The study was conducted on a farm located in the central plain region of Israel during November 1990. on lambs of mixed breeding (Merino/Cambridge) aged approximately 4 months and weighing 30~35 kg. The lambs were divided into three experimental groups ( 3 per group), each group being kept in separate pens; they were fed once a day with commercially available concentrated feed pellets, hay and water being available ad libitum. In Experiments 1 and 2 , Ivermectin in the form of a 1% w/v cattle injection ("Ivomec" (R) , Merck, Sharp and Dome, B.V. , Haarlem, Netherlands) was used; in Experiment 3. Ivermectin extracted from this commercial formulation was used, and this extract also served as the standard for the analytical procedure (the extraction efficiency was about 90%).

Experiment 1.

"Ivomec" ( 1 ml., containing 1G mg. Ivermectin) was injected subcutaneously into two male lambs (#657 and #6 1 ) and one female lamb (#775 ) · Venous blood samples ( 10 ml.) were taken from the jugular vein of each lamb before administration of the medicament and then at 1 , 2 and k hours thereafter. Blood samples were then taken every morning for the next 5 days.

Experiment 2 This experiment was carried out on two male lambs (#663 and #671 ) and one female lamb (#763 ) . To the left ear of each lamb, 22u and without shaving or preparing the skin surfaces in any manner, there was attached an AV-DDS device containing as matrix a Ί mm. thick Spontex(R) absorbent sponge in which circular perforations of k mm. diameter were made, the centers of which were approximately 8 mm. apart. The surface area of each matrix was 110 cm.2, i.e. 55 cm.2 applied to the outer and inner surfaces of the ear, respectively. Each matrix was impregnated prior to attachment, with 16 ml. soybean oil. Three layers of absorbent paper towels, perforated in the same manner as the sponge, were then attached to each matrix, the paper towels being impregnated with l6 ml. of "Ivomec". Thus each matrix contained approximately 160 mg. of Ivermectin, the preparation being referred to herein as dosage form "A" . The system was maintained on lamb #663 for 7 consecutive days, on lamb #671 for 16 consecutive days, and on lamb #7 3 for 18 consecutive days. Venous blood samples (10 ml . ) were taken from the jugular vein of each lamb before administration of the medicament and then at 1, 2 and 4 hours thereafter. Blood samples were then taken every morning for the next 8, 17 and 18 days, respectively.

Experiment 3_ This experiment was carried out on two female lambs (#760 and #778) and one male lamb (#665). A composition containing Ivermectin which had been extracted from "Ivomec" according to Oehler and Miller (Journal of the Association of Official Analytical Chemists, USA, 1989, 72(1): 59) was prepared (and determined on HPLC, the lower limit of detection being 3 ng./ml.). In order to prepare the composition, this extract 22v 95508/1 containing about 90 Ivermectin was dissolved in soybean oil to give a concentration of medicament of approximately 10 mg./ml. To the left ear of each lamb, and without shaving or preparing the skin surfaces in any manner, there was attached an AV-DDS device containing as matrix a k mm. thick Spontex(R) absorbent sponge in which circular perforations of Ί mm. diameter were made, the centers of which were approximately 8 mm. apart. The surface area of each matrix was 110 cm.2, i.e. 55 cm.2 applied to the outer and inner surfaces of the ear, respectively. Each matrix was impregnated prior to attachment, with 8 ml. soybean oil, allowed to stand for several minutes, and then impregnated with 16 ml. of the composition. Thus each matrix contained approximately 160 mg. of Ivermectin, the preparation being referred to herein as dosage form "B" . The system was maintained on each lamb for 17 consecutive days. Venous blood samples (10 ml.) were taken from the jugular vein of each lamb before administration of the medicament and then at 1, 2 and 4 hours thereafter. Blood samples were then taken every morning for the next 19 days.

Results Ivermectin serum concentrations, as determined by HPLC, are shown in Table 7t below. Prior to administration of the medicament, no Ivermectin could be detected in any of the lambs' sera.

In Experiment 1, each of the three lambs was injected subcutaneously with 10 mg. Ivermectin, which was first detected in blood samples taken hours after administration in lamb #6 1, 22w 95508/1 and in blood samples taken 2k hours after injection in lambs #657 and #775 · Ivermectin was detected in blood samples taken up to day Ί in lamb #651 and up to day 5 in lambs #657 and #775 · In Experiment 2, the three lambs were treated with dosage form "A" as described; no Ivermectin could be detected in any of the blood samples.

In Experiment 3 t using dosage form "B", Ivermectin was detected in blood samples taken from lamb #665 , from hours after administration up to day 13 ; in lamb #760, from 2 hours up to day 17 ; and in lamb #778 , after day 2 and up to day l .

Discussion of results Owing to the fact that pure Ivermectin could not be readily obtained, it was necessary to extract this medicament as an approximately 90. pure product, from the commercially available formulation, as described above, in order to prepare dosage form "B" and to serve as the standard for the analytical procedure. Since Ivermectin has been reported as having the property of binding to many surfaces including glass and plastics, it seems likely that the Ivermectin serum concentrations reported in the present study were probably underestimates because the analysis vessels were not coated to prevent such binding. In spite of these difficulties, it may be concluded that Ivermectin can be administered transdermally to sheep for an extended period of time, as demonstrated in Experiment 3. above, in which dosage form "B" was incorporated into the AV-DDS device as described. Given the primitive nature of this dosage form, it was demonstrated that Ivermectin can be 22x administered transdermally for 13 days, and perhaps even for a longer period.

The advantages of transdermal administration of Ivermectin in accordance with the invention would be that serum concentrations of this medicament can be maintained for an extended period of time and that the treatment can be readily terminated, by simply removing the dosage form from the skin.

Table ]"_: Ivermectin serum concentrations of lambs treated with three different dosage forms.

Ivermectin Serum Concentration (ng./ml.) Mode of subcutaneous dosage form "A" dosage form "B" Administration injection Lamb # 651 657 775 663 671 763 665 760 778 Time 0 0 0 0 G G G 0 0 0 1 hour G 0 0 G G G 0 0 0 2 hours 0 0 0 0 0 G G G 0 4 hours 9 0 0 G G G * G G Day 1 - 20 6 G G G 8 15 G Day 2 14 17 42 G 0 0 14 17 4 Day 3 19 8 15 G G G 14 18 5 Day 4 6 - 14 G G G 12 18 6 Day 5 0 15 49 0 G G 9 14 4 Day 6 G G G 8 11 4 Day 7 G G G 8 13 7 Day 8 G G 0 7 16 4 Day 9 G 0 6 7 4 22y Table 2 (continued) Day 10 0 0 6 6 * Day 11 0 0 * 6 * Day 12 0 0 ' » * * Day 13 0 0 # * * Day 14 0 0 0 * Day 15 0 0 0 * 0 Day 16 0 0 0 * 0 Day 17 0 0 0 * 0 Day 18 0 - 0 0 Day 19 0 0 0 ADVANTAGES OF THE INVENTION systems of transdermal administration in practice limited to application of one particular drug; they are generally restricted to application for 3~4 days (or exceptionally up to about 7 days); and they are usually unsuitable for applying to hairy surfaces.

By contrast, the pharmaceutical compositions of the invention can contain a plurality of medicaments for simultaneous administration, which is convenient and ensures patient compliance. The device of the invention containing the pharmaceutical compositions can be applied for 2-3 weeks, or more, as necessary, and is not restricted to application at non-hairy skin surfaces; moreover, unlike existing systems, the present device can be removed for the purpose of bathing the skin and can subsequently be re-applied to the same site. 22z Further advantages of the invention in contrast with some of the prior art methods, are that is unnecessary to adjust the pH of the administered composition, or to ensure that the administered medicament is completely soluble in the carrier; preparation of the compositions is uncomplicated; and the same or similar carriers are effective for different kinds of drugs.

While particular embodiments of the invention have been particularly shown and/or described hereinabove, it will be appreciated that the present invention is not limited thereto, since, as will be readily apparent to skilled persons, many variations and modifications can be made. Accordingly, the essential concept, spirit and scope of the present invention will be better understood in the light of the claims which follow. 23 95508/4

Claims (22)

1. A pharmaceutical composition for use in the transdermal administration of a medicament, which composition comprises an effective amount of a medicament adapted for transdermal administration, in combination with a transdermally transporting effective amount of an essentially non-aqueous carrier for the medicament, which carrier is selected from semisolids and liquids at ambient temperatures, and which carrier comprises at least one compound selected from esters, excepting monoesters, of ^Q-2k fatty acids, pharmaceutically acceptable aliphatic polyhydroxy compounds and non-volatile paraffins, provided that when said carrier comprises 80~99# of said polyhydroxy compounds, it does not simultaneously comprise 1-20$ fatty component selected from linoleic acid, its (1-3C) esters and monohydroxy linoleyl alcohol.

2. A composition according to claim 1, wherein the medicament comprises at least one member selected from reproduction modulating agents, anthelmintics, antibiotics, antiparasitics, antiinflammatory agents, bronchodilating agents, cardiovascular agents and antiallergic agents .

3. · A composition according to claim 2, wherein the medicament comprises at least one member selected from the following sub-groups, namely: (i) reproduction modulating agents: estradiol, progesterone, medroxyprogesterone, medroxyprogesterone acetate, megestrol acetate and testosterone; (ii) anthelmintics t levamisole, ivermectin, mebendazole and pyrantel; (iii) antibiotics : semisynthetic penicillins, tetracyclines and cephalosporins ; 2k 95508/3 (iv) antiparasitics ; metronidazole; (v) antiinflammatory agents ; diclofenac sodium, ibuprofen and indomethacin; (vi) bronchodilating agents : aminophylline, theophylline, terbutaline and salbutamol; (vii) cardiovascular agents : propanolol, metoprolol and clonidine ; (viii) antiallergic agents: chlorpheniramine and mebhydroline .

4. . A composition according to any of claims 1~3 , wherein the alcohol component of the ester is derived from an aliphatic hydroxy compound containing 1-12 carbon atoms and 1-3 hydroxy groups .

5. · A composition according to claim 4 , wherein the acid component of the ester is selected from caprylic, capric, lauric, palmitic, stearic, arachidic, behenic, lignoceric, oleic, elaidic, petroselinic, linoleic, alpha-linolenic (9 , 12 , 15-octadecatrienoic acid), gamma-linolenic, linolelaidic, arachidic, 11-eicosenoic, 11 , 14-eicosadienoic, 11 , 14 , 17-eicosatrienoic, arachidonic, 5 ,8 , 11,14, 17-eicosapentaenoic, erucic and nervonic acids.

6. A composition according to any of the preceding claims, wherein the carrier for the medicament comprises at least one member selected from the group consisting of diglycerides , triglycerides, and mixtures thereof, of at least one Cg_2_| fatty acid. 25 95508/2

7. · A composition according to claim 6 , wherein the carrier comprises at least one member selected from natural fats and oils, and fractions thereof.

8. A composition according to any of the preceding claims, which contains an additional medicament selected from antiinflammatory agents and antihistamines, in order to mitigate any skin-incompatibility characteristic which may otherwise be present.

9. A composition according to claim 7 » wherein the carrier comprises at least one member selected from peanut, almond, walnut, rapeseed, soybean, corn and liquid coconut oils.

10. A composition according to claim 7. wherein the carrier comprises a natural oil in which a major proportion of the fatty acid content consists of CiQ-2k polyunsaturated fatty acids.

11. A composition according to claim 10, wherein a major proportion of said fatty acid content of the natural oil is selected from linoleic and linolenic acids.

12. A composition according to claim 6 , wherein the carrier comprises at least one ester of at least one ^ΐβ-^Ί polyunsaturated fatty acid.

13. A composition according to claim 12 , wherein the carrier comprises a major proportion of at least one ester of at least one polyunsaturated fatty acid. 26 95508/3

14. A composition according to claim 13, wherein the carrier comprises a major proportion of at least one ester of at least one acid selected from li'noleic and linolenic acids.

15. 1 . A composition according to claim 1, wherein said pharmaceutically acceptable aliphatic polyhydroxy compound is selected from glycerol and propylene glycol.

16. A pharmaceutical composition for use in the transdermal administration of a medicament, which composition comprises an effective amount of a medicament adapted for transdermal administration, in combination with a transdermally transporting effective amount of an essentially non-aqueous carrier for the medicament, which carrier is selected from semisolids and liquids at ambient temperatures, and which carrier comprises at least one compound selected from esters, excepting monoesters, of CQ_2_J fatty acids, pharmaceutically acceptable aliphatic polyhydroxy compounds and non-volatile paraffins, provided that said esters comprise at least ^0% by weight of at least one ester of at least one fatty acid.

17. A composition according to claim 16, wherein the carrier comprises at least 7 by weight of said at least one ester of at least one fatty acid.

18. A composition according to claim l6, wherein the carrier comprises at least 90% by weight of said at least one ester of at least one C1g_2zj fatty acid. 27 95508/3

19. · Use of a pharmaceutical composition according to any of the preceding claims in the manufacture of a medicament for transdermal administration to humans, said manufacture including absorption of said pharmaceutical composition on a porous, absorbent perforate and flexible laminar solid support.

20. Use according to claim 19, wherein a flexible breathable backing layer is adhered to one side of said laminar solid support, said backing layer having less absorbability for said pharmaceutical composition, than said flexible laminar solid support.

21. Use according to either claim 1 or claim 20, wherein said laminar solid support is configured to provide a desired controlled or sustained release pattern for said pharmaceutical composition.

22. Use according to claim 19, wherein a flexible breathable backing layer is adhered to one side of a multilayer system providing a desired controlled or sustained release pattern for said pharmaceutical composition, wherein said multilayer system includes said laminar solid support and at least one other layer such that at least two individual layers in said system possess different absorbabilities for said pharmaceutical composition, and said backing layer has less absorbability for said pharmaceutical composition than any of the individual layers in said multilayer system. For the Applicants, Sanford T. Colb & Co. C: 11061 1-1124 28